Time for a drink! Patrick Schwarzenegger, 18, hits the London club scene with sister Katherine

By Virginia Skeels

Published: 12:14 EDT, 12 August 2012 | Updated: 03:00 EDT, 13 August 2012

Patrick Schwarzenegger can drive, vote and own a gun in California.

But the handsome 18-year-old can't order an alcoholic beverage at a bar, with the legal drinking age in his home state set at 21.

It makes perfect sense, then, that Arnold Schwarzenegger's son has been making the most of London's night life while on holiday in the U.K.

The model, entrepreneur - and most recently actor - was spotted last night with his sister Katherine, 22, at Chinawhite nightclub, one of London's most high-profile celebrity haunts.

Hitting the town: Patrick and Katherine Schwarzenegger leaving London celebrity haunt Chinawhite last night

The siblings, likely in town for the closing ceremony of the Olympics, were snapped leaving Chinawhite in high spirits.

Patrick - who owns his own clothing line - had barely a hair out of place despite the late hour, looking smart in a collared short-sleeved checked shirt, jeans and white sneakers.

His sister Katherine wore black skinny jeans and a navy and white striped shirt under a black jacket with leather sleeves and black suede boots.

All grown up: In his home state of California, 18-year-old Patrick can't go to most clubs as they are over-21, but in the UK he gets to let his celebrity hair down

The eldest child of Maria Shriver and Arnold, Katherine graduated with a journalism degree, and like her mother is a journalist and author.

Patrick, meanwhile, started his own company when he was just 15, a clothing line called Project 360.

Started with the help of his parents, the philanthropic clothing line has a full menswear collection and a mid-five-figures net from 2010, according to Details magazine.

The company donates 10 percent of all its sales to a variety of charities.

Patrick is also signed with L.A. Models, and was as recently as July romantically linked to singer Taylor Swift.

Model citizen: The third child of Arnold Schwarzenegger and Maria Shriver owns a philanthropic fashion clothing line, is signed with a modelling agency, and has more recently started acting

The teenager also recently started acting. He has just completed filming in a new movie called writers, starring Kristen Bell, and has an upcoming role in Grown Ups 2, starring Adam Sandler.

Patrick was ringside this morning at the men's basketball gold medal game between the United States and Spain on Day 16 of the London Olympics.

His other sister Christina, 21, sat with him to his right, and next to her was Christina.

Joining the Schwarzenegger kids was Facebook actor Jesse Eisenberg, reaching for an incognito look in a red cap and lumberjack shirt.

Sister number two: Patrick was courtside with his other sister Christina today for the men's gold medal basketball game between the U.S. and Spain

Star power: Actor Jesse Eisenberg joined Katherine, Christina and Patrick Schwarzenegger courtside

The Schwarzenegger-Shriver children arrived in London this week after vacationing with their mother in Nantucket, and Katherine was seen in Paris with her father last week.

The chidlren's high-profile parents have kept a much lower profile since their split in May last year, after 25 years of marriage.

The separation was made public just a week before news that Schwarzenegger had fathered a lovechild with an employee in the couple’s household 14 years earlier.

Arnold and 56-year-old Maria have four children together: Katherine, 22, Christina, 21, Patrick, 18, and Christopher, 14.